Pressure-balanced segmental packing rings



Sept. 6, 1966 F. E. HAMMOND 3,271,037

PRESSURE-BALANCED SEGMENTAL PACKING RINGS Filed April 1, 1 963Sheets-Sheet 1 Z as 22 22 Tia. '5 Z8 INVENTOR: fiwA/A ZflA/W/Wa wArroEA/Ei P 6, 1966 F. E. HAMMOND 3,271,037

PRESSURE-BALANCED SEGMENTAL PACKING RINGS Filed April 1, 1963 5Sheets-Sheet 2 59 1 57 5/ 1 J 7 m 26 INVENTOR:

Tic E BY p 6, 1966 F. E. HAMMOND PRESSUREBALANCED SEGMENTAL PACKINGRINGS Filed April 1, 1963 5 Sheets-Sheet 5 I: in. l 4' 24 24 29 zf fz wATTU/QA/EI/ United States Patent 3,271,037 PRESSURE-BALAN CED SEGMENTALPACKING RINGS Frank E. Hammond, Palmyra, N.Y., assignor to Garlock Inc.,Palmyra, N.Y., a corporation of New York Filed Apr. 1, 1%3, Ser. No.269,617 1 Claim. (Cl. 277-27) This invention relates to segmentalpacking rings such as are employed for effecting a seal at high pressurebetween a machine casing and a rod or shaft which extends through andreciprocates or rotates in an opening in said casing. Without limitationthereto, reference is hereinafter made only to a reciprocating rod ascomprehending also a shaft. Although the subject segmental rings aredisclosed herein, for illustrative purposes, as being of metal, itshould be understood that they may be of other suitable relativelynon-deformable, hard, or rigid material.

Such rings are commonly formed of three or more similar segments whichfit closely together and are so shaped, with tangential, inter-abuttingedges, that the pressure of sealed fluid, directed radially inwardlyupon the outer periphery of the ring, urges the segments radiallyinwardly into substantially fluid-tight association with a reciprocatingrod extending through the ring. Such rings commonly have a smooth sidesealing face at a rear side thereof which face, under pressure of sealedfluid, applied axially to the opposite or pressure side of the ring,forms a substantially fluid-tight seal with a related backup ring orwith a wall of a container assembly within which it is mounted. Suchsegments, independently of such pressure, are commonly held together inco-planar relationship by a garter spring.

The mentioned radially directed fluid pressure and the axially directedfluid pressure give rise, in rings hitherto employed, to a very forcefulsealing engagement of the rings segments with the rod and with the sidewall of a related container, thereby causing relatively rapid wear ofthe rings se ments and/or of the rod and the container wall.Additionally, such forceful sealing engagement of the composite ringwith the rod gives rise to excessive power losses.

An important object of this invention is to provide a segmental packingring which substantially eliminates all excessively forceful engagementof the rings segments, both with a rod extending through the ring andwith a side wall of a related container to minimize wear and powerlosses.

The foregoing and other more or less obvious objects are accomplished,according to the broader aspects of this invention, by forming thesegments of the packing ring with balancing surfaces which are exposedto the high pressure of the sealed fluid. The conformation of thesegments is such that the force of radially inwardly directed fluidpressure imposed upon the segments of the ring is largely offset by theforce of fluid pressure applied to balancing surfaces of the ringexerting a radially outwardly directed opposing force. The rings,according to this invention, also may be formed with balancing surfacesupon which the pressure of the sealed fluid is effective axially inopposition to the fluid pressure urging the ring against a side wall ofa related container.

Several embodiments of this invention are shown in the accompanyingdrawings for illustrative purposes, it being understood, however, thatthis invention is not limited to such illustrated embodiments.

In the drawings:

FIGURE 1 is a central vertical sectional view through ice a portion of amachine casing showing, associated therewith, a preferred embodiment ofsegmental packing rings and packing ring sets according to thisinvention, employed for effecting a seal between the machine casing anda rod extending through an opening in said casing.

FIG. 2 is a side elevational view, as from the plane of the arrows 2-2of FIG. 1, of a radially split, segmental back-up ring such as isusually employed in practicing this invention, in side-by-siderelationship with a tangentially split, segmental, packing ring, in thearrangement illustrated in the latter figure; the opposite side surfacesof this back-up ring being uninterruptedly planar, except for dowelprovisions hereinafter detailed.

FIG. 3 is a side elevational view, as from the plane of the arrows 33 ofFIG. 1, of the rear side of a tangential, segmental, packing ring, asillustrated in the latter figure.

FIG. 4 is a side elevational view, as from the plane of the arrows 44 ofFIG. 1, of the opposite or pressure side of the tangential ring shown inFIGS. 1 and 3.

FIG. 5 is a fragmentary sectional view of a set of the packing andback-up rings illustrated in FIG. 1, showing a dowel pin arrangement forpreventing relative rotation of the two rings to keep their splits innon-alignment with each other.

FIG. 6 is a vertical sectional view somewhat similar to the upperportion of FIG. 1 but illustrating the use of modified tangential ringsaccording to a second embodiment of this invention.

FIG. 7 is an elevational view of the rear side of the tangentially splitpacking ring illustrated in FIG. 6.

FIG. 8 is a radial sectional view of the tangential ring shown in FIGS.6 and 7, substantially on the irregular line 88 of the latter figure.

FIG. 9 is an elevational view of the pressure side of the tangentialring shown in FIGS. 6, 7, and 8.

FIG. 10 is a vertical sectional view somewhat similar to FIG. 6 butillustrating the use of further modified tangential rings according to athird embodiment of this invention.

FIGS. 11, 12, and 13 are views generally similar in character,respectively, to FIGS. 7, 8, and 9, illustrating, however, thetangential ring shown in FIG. 10; the section shown in FIG. 12 beingsubstantially on the line 12-12 of FIG. 11.

FIG. 14 is a view somewhat similar to FIG. 10 illustrating, however, afourth embodiment wherein tangential packing rings, according to thisinvention, are employed without any related back-up ring.

FIG. 15 is a view similar to FIG. 14 showing, however, a fifthembodiment of this invention wherein a single backup ring is employed inassociation with one (usually the outermost) of plural tangential rings;the latter being illustrated as of the same character as the tangentialrings of FIGS. 10-14.

FIG. 16 is a view generally similar to FIG. 1, illustrating, however,the use of only a single set of segmental packing rings according tothis invention; the tangential ring being shown as like thoseillustrated in FIGS. 1, 3, and 4 (although, optionally, it could be ofany other suitable form within this invention), while the back-up ringis solid rather than segmental.

FIG. 17 is a perspective view of the back-up ring of FIG. 16.

High pressure, as referred to herein, contemplates all fluid pressureswhich, in the use of .prior segmental packing rings not embodying thisinvention, would give rise to the mentioned excessive wear and powerlosses. Segmental seals, according to this invention, are particularlyuseful in sealing gases which are contained at rela- Patented Sept. 6,1966 V tively high pressure and in most applications use would be madeof plural segmental packing rings or sets of such rings.

Referring to FIGS. 1-5, a machine casing wall is shown as formed with abore 21 through which extends a rod 22. A counterbore 23, formed in thecasing wall, constitutes a packing recess accommodating tightlytherewithin a series of three angular ring containers 24, held in placeby a closure plate 25 which is suitably secured to the casing wall byplural machine screws 26.

The containers 24 are similarly of angular shape in cross-section, andeach has, in an internal rabbet 24a thereof, a packing ring setconsisting of a back-up ring 27 and a tangentially split-packing ring28. The inside diameter of the rabbet 24a is substantially greater thanthe outside diameters of the rings 27 and 28, thereby providing afluid-pressure chamber 29 extending about the outer peripheries of saidrings; and the axial dimension of said rabbet is at least slightlygreater than the combined ax-ial thicknesses of said rings.

Back-up ring 27 is a segmental ring comprising, as shown in FIG. 2,three segments 30 abutting each other at radial splits 31; and the threesegments are held together by means of a garter spring 32 which istensioned about the periphery of the thus constituted ring and seatswithin a circumferential groove 33 extending about all three segments.Because of the fact that the splits 31 extend radially, as illustrated,the constituted ring is limited as to its inside diameter, which is onlyslightly larger than the diameter of the rod 22 to provide a freesliding fit therewith.

The packing rings 28, illustrated in FIGS. 15, are all alike. Each isconstituted of three similar segments numbered 34 which, however, abuteach other at splits 65 which are tangential to the inside cylindricalsurface of the composite ring. The segments 34 are held together by atensioned garter spring 36 seated in a peripheral groove 2811. Thus, thepacking ring 28, because of its tangential split arrangement, is capableof closing-in radially to compensate for wear which may occur at theinside of the ring during operation. As it is desirable, for sealingpurposes, to keep the splits 31 of ring 27 out of alignment with thesplits of ring 28, the two mentioned rings are held in such non-alignedcondition and against relative rotation by any suitable means as, forexample, by dowel pins 37 which may be provided in the segments 34 ofring 28 and which extend axially into recesses 38 of the segments 30 ofring 27, these recesses preferably being oversize at least radially ofthe ring to allow for the mentioned wear-compensating closing-in of thesegments of ring 28.

The inventive aspects of the ring 28 reside chiefly in certainconformations thereof providing oppositely facing pressure-receptivesurfaces which cause the segments 34 of ring 28 to be subjected tocounteracting forces from the pressure of sealed fluid directedradially, both inwardly and outwardly, and/ or axially in oppositedirections to minimize wear as hereinbefore mentioned.

The pressure side of the composite ring 28 is formed with a continuousinner circumferential recess or rabbet 39 defined radially by an annularland 40, at the outer periphery of the ring.

The rear side of the composite ring 28 is formed with an annular land 41at its inner periphery and, at its outer periphery, a circular series ofrelatively long, equidistantly spaced, arcuate lands 42 and smallerlands 43 equally spaced, in said series, between the lands 42.

In considering the manner in which the pressure of sealed fluid iscaused to impose counteracting forces on the segments of the tangentialring 28 to achieve the stated objects of this invention, it should benoted that fluid pressure at P (FIG. 1) is communicated along the rod 22.into rabbet 39, thereby urging the ring set RS axially outwardlyagainst radial flange 24b of the center ring container 24 and enablingthe fluid pressure to be communicated radially outwardly past thepressure side of the innermost ring 28 into pressure chamber 29surrounding the latter ring and thence, into a pressure chamber 44constituted of channels 45 between the several lands and a circularchannel 46 between the annular land 41 and the series of lands 42, 43.

It will be understood that, with uniform unit pressure of the sealedfluid present in areas as just indicated, the force of fluid pressureimposed axially outwardly upon the exposed entire, axially facingsurfaces of the pressure side of the innermost ring 28 is substantiallybut not completely counteracted by the force of the fluid pressureimposed axially inwardly upon said ring in the pressure chamber 44, theexposed, axially facing surfaces of which are of lesser total area thanthe oppositely, axially facing surfaces of the pressure side of saidring 28. Thus, the described land and channel configuration of the rearside of ring 28 causes the latter to bear relatively lightly against itsrelated back-up ring 27, thereby minimizing side-surface wear andsubsequent distortion incident to the use of prior metal packing rings.

It will also be understood that the force of fluid pressure in pressurechambers 29 and 44, effective radially inwardly upon radially outwardlyfacing cylindrical surfaces defining said chambers, is verysubstantially but not completely counteracted by the force of fluidpressure, effective radially outwardly upon radially inwardly facingcylindrical surface 47 defining rabbet 39 and upon radialily inwardlyfacing arcuate surfaces 48 and 49, respectively, of the several lands 42and 43. Thus, the described rabbet, land, and channel configurations ofthe two sides of ring 28 cause the segments of the latter to bearrelatively lightly upon the rod 22, thereby minimizing wear of theinterengaging surfaces of said segments and said rod and also minimizingpower losses.

The foregoing description of the effect of counteracting pressure forcesupon the innermost ring '28 also applies to the rings 28 of the twoother illustrated ring sets, it being understood that each of said twoother ring sets is operative only with respect to the pressure of fluidwhich may have escaped past a preceding, more inwardly located one ofsaid ring sets.

It will also be understood that the degree of balancing of the rings 28(i.e., the relationship of counteracting fluid pressure forces), may beconsiderably varied to adapt such rings for use under various operatingconditions. Such variation may be effected by suitably varying thedimensions of the different pressure-responsive surfaces of the ringsas, e.g., by changing the width of the channels 45, by changing thedepth of the pressure chamber 44 and by changing the dimensions of therabbet 39.

The second embodiment, illustrated in FIGS. 6-9, differs from thealready detailed first embodiment chiefly in that, at the pressure side(FIG. 9) of each of the three similar tangential rings 28b, radialchannels 51 are provided, freely interconnecting a continuous rabbet 39awith pressure chamber 29; and said channels 51 may serve two purposes.First, they may serve to change the radial balance of the ring, ascompared to such balance in a ring according to the first embodiment,because the radially inwardly facing cylindrical surfaces 52 and 53 oflands 54 and 55, formed by the provision of said channels, present lesspressure response area than is presented by the surface 47 of FIGS. 1and 4. Second, the channels 51 afford free fluid communication betweenrabbet 39a and pressure chamber 29, thereby permitting the set of rings27, 28b to fit quite closely, but nevertheless freely slidable radially,between radial flanges of successive ring containers 24. Such fit in thefirst embodiment would be less close to assure fluid communication tochamber 29.

It may be observed that the segmental rings 28 and 28b of the first twodetailed embodiments are quite thin or narrow, this being desirable inorder to minimize the axial dimension of the entire packing assemblyprovided for the rod 22. This narrowness is accentuated by the cuttingout of the rabbet 39a and the pressure chamber 44. But for an importantfeature of this invention, the thin segments of the rings 2-8 and 28btend to wobble, in operation, as a result of the varying fluid pressureforces imposed upon their side faces. The mentioned feature is thedisclosed arrangement wherein the lands 42 of the first embodiment (FIG.3) and the corresponding lands of the second embodiment (FIG. 7) as wellas the latter embodiments lands 54 (FIG. 9) extend across tangentialsplits at which the segments abut. Thus, the ends of the segments, atthe outer periphery of the segmental ring, are given substantial widthand resultant full support against wobbling. The intermediate, smallerlands 43 (FIGS. 3 and 7) provide support between the lands 42 both tooppose wobbling and to oppose distortion of the segments by fluidpressure imposed upon the pressure sides of the segments.

The third embodiment, illustrated in FIGS. 10-13, differs from the firstand second embodiments in a substantial change of form of the threesimilar tangential rings 28:: which are tangentially split similarly torings 28 and 2812. Referring to the innermost or most rightward of therings 28a of FIG. 10 for description, also of the other two identicalrings 28c, the pressure side of the ring 280 FIG. 13), like the pressureside of ring 28b (FIG. 9), is formed with a discontinuous inner marginalrabbet 69a, in fluid communication with pressure chamber 29 throughradial channels 51; said rabbet and channels derfining lands 54 and 55.The rear side of ring 280 (FIG. 11), except for separate peripheral bays56, has a flat land surface 57.

Each ring 28c is formed with a radially inwardly facing groove 58, andaxial apertures 59 afford free communication of fluid pressure from thepressure side of the ring to said groove.

It will readily be seen that, with tangential rings 28c, fluid pressureeifective axially inwardly upon the bottom surfaces 56a of the bays 56operates to counteract, in a measure, the axially outwardly directedforce of the fluid pressure applied to the pressure side of the ring;and fluid pressure effective radially outwardly upon the cylindricalbottom area 58a of groove 58 operates to counteract, in a measure, theradially inwardly directed force of the fluid pressure applied to theouter peripheral surfaces of the ring at pressure chamber 29.

FIG. 14 merely illustrates that tangential rings within this inventionmay be employed without any back-up rings, in which arrangement the twoinnermost tangential rings (shown for illustrative purposes as rings280), are pressure urged against radial flanges 24b of the two outermostcontainers 24 and the outer tangential ring is urged by fluid pressureagainst the inner face 25a of closure plate 25.

FIG. shows that, under some conditions, it may be desirable to employ asingle back-up ring 27 disposed between the outermost tangential ringand the closure plate 25.

FIG. 16 shows that, under some conditions, a smgle set of rings may beemployed in a single container 24 and directly held in place by plate25. In this set of rings, the tangential ring is shown, for illustrativepurposes, as a ring such as is shown at 28 in FIGS. 1-5. The back-upring, however, is shown, for illustrative purposes, as a continuous ornon-split ring 60.

It should be understood that either a split back-up ring 27 or acontinuous back-up ring 60 or equivalents of either of these rings maybe employed with any tangential ring within this invention. The dowelarrangement, shown at 37, 38 in FIGS. 2-5, should preferably be employedwhen a split back-up ring is employed but is not necessary when acontinuous back-up ring is used.

One familiar with the subject art will perceive that the various formsof tangential rings disclosed herein serve, as examples, to show variousways in which such rings may be formed to give rise to fluid pressureforces acting upon the ring in opposition to fluid pressure forcesacting thereon radially inwardly and/ or axially outwardly. Moreover,the extent or value of such opposing forces may, of course, be quiteminutely varied or proportioned to the opposed forces by suitablyvarying the dimensions of the disclosed lands, channels, grooves, andthe several pressure chambers generally.

It is Worthy of note that, at the rear sides of the tangential rings,the land areas extend substantially along or into marginal areasbordering the outer and inner peripheries of the rings. This affordssupport for the ring against the axially outwardly directed force of thehigh fluid pressure of the sealed fluid, thereby opposing distortion ofthe ring.

It should also be understood that the inventive concepts disclosedherein may be practiced in various other ways without, however,departing, from this invention as set forth in the following claim.

I claim:

A segmental packing ring comprising segments, of substantiallynon-deformable material, which are in abutment at axially extendingsurfaces of tangentially extending splits; said segments having radiallyoutwardly facing surfaces receptive to fluid pressure directed radiallyinwardly thereon to urge the segments forcefully against a rod extendingthrough said ring and each of said segments being formed with spacedarcuate lands extending circumferentially of the ring and havingradially inwardly facing surfaces receptive to fluid pressure directedradially outwardly thereon to oppose said radially inwardly directedpressure and thereby ease the engagement of said segments with the rod;said lands on each segment being located adjacent the segments outercircumferential surface and at the tangentially extending splits atopposite ends of the segment in abutment with similarly located arcuatelands of adjacent segments, whereby to provide lateral support at theouter periphery of the ring against wobbling of the segments thereof;said lands, further, being provided at both the pressure side and therear side of the ring.

References Cited by the Examiner UNITED STATES PATENTS 1,331,360 2/ 1920Parsons et a1. 277-27 1,828,178 10/1931 Fox 277-- 1,999,094 4/ 1935Godron 277-27 FOREIGN PATENTS 28,252 3/ 1931 Australia.

SAMUEL ROTHBERG, Primary Examiner.

E. DOWNS, Assistant Examiner.

